This tutorial should explain how to avoid Cartesian Products

[clem]

In this tutorial:

Neo4j Graph Database Platform

Creating Relationships - Introduction to Neo4j 4.x Series

There is the query:

MATCH (a:Person), (m:Movie)
WHERE a.name = 'Michael Caine' AND m.title = 'Batman Begins'
CREATE (a)-[:ACTED_IN]->(m)
RETURN a, m

with an explanation that this query will create a cartesian product but it does NOT explain how to avoid that!

Avoiding a cartesian product is explained here:

Avoid cartesian product when create relationships Cypher

Hi! I'm new to neo4j and I try to find some help here. I have two sets of nodes say one is people and another is car.I want to create relationship between these two sets of nodes but I don't want to create relationships base on cartesian product of result return by match since it will take much time. The cypher statement I use like below: MATCH (a:test_11),(b:test_12) WHERE a.car ="0" AND b."price" = "1" MERGE (a)-[r:own{time:2020,location:"LA"}]->(b) Is there a way to write cyher which ca…

(I would have made a Pull Request on it, but I don't know where it lives in github.)

[dana_canzano]

Yes that cypher statement does create a Cartesian join but it's a 1x1 Cartesian since each match returns only 1 row given the data model

[clem]

That's not the point of my suggestion.

I got the warning but I didn't have any idea of how to fix it until today.

It's not immediately obvious how to not do a Cartesian Product.

[benjamin_rood]

@dana_canzano It's rather shameful when people wilfully miss the point and dismiss very reasonable issues in documentation. Not very good advert for your product, is it?